// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
#nullable disable
 
using System;
 
namespace Microsoft.CodeAnalysis.Internal.Log
{
    /// <summary>
    /// An interaction class defines how much time is expected to reach a time point, the response 
    /// time point being the most commonly used. The interaction classes correspond to human perception,
    /// so, for example, all interactions in the Fast class are perceived as fast and roughly feel like 
    /// they have the same performance. By defining these interaction classes, we can describe 
    /// performance using adjectives that have a precise, consistent meaning.
    /// </summary>
    internal enum InteractionClass
    {
        Undefined, // use when we don't have a specific goal for this operation
 
        // Name             Target (ms)     Upper Bound (ms)        UX / Feedback
        Instant,         // <=50            100                     No noticeable delay
        Fast,            // 50-100          200                     Minimally noticeable delay
        Typical,         // 100-300         500                     Slower, but still no feedback necessary
        Responsive,      // 300-500         1,000                   Slower yet, potentially show Wait cursor
        Captive,         // >500            10,000                  Long, show Progress Dialog w/Cancel
        Extended,        // >500            >10,000                 Long enough for the user to switch to something else
    }
 
    [AttributeUsage(AttributeTargets.Field, AllowMultiple = false, Inherited = false)]
    internal class PerfGoalAttribute : Attribute
    {
        private readonly InteractionClass _interactionClass;
 
        public PerfGoalAttribute(InteractionClass interactionClass)
            => _interactionClass = interactionClass;
 
        public InteractionClass InteractionClass => _interactionClass;
    }
}